Method of forming lamp filaments



Filed ma ug; 1949 O.MANN EfAL 7ZmWaS INVENTORj AT-roRNe Y owzo, 1953 o. MANN- ETALT 2,655,952

METHODOF FORMING LAMP F ILAMENTS I0. I 28 O/imr Mann INVENTORS Arromvgv Ra/ph 5. 7770mas,

Patented Oct. 20, 1953 o Ic-e' Ql e'ti Mi la e nevwg A m and Ralph B. Thomas, Mass assignors "wsywania .Elctii" 4 c Sa em ess-s o p a n A pl cation May. 28, 19 9,S .ia1No. 95,986

ments'and more particularlv't'o fila s' 'gf'the yn e hhhredih high-Wa g am s su h" he projection 1an'1ps,'for egainf l. h h m hhi e' hf q 'h h his'i r'hr e tieh 5 lam s e he'ci l fih hi 9 hi-h hh t e; hhh id rab haie h h f her ised t hsu e uniform length the se era eemeht hit e filam nt uhiihr i swi e'h ehq'h 'seelheht hdh er ha h th e lhes'e t e Segments; s 'c'e a mi eerament hi highquality requires very close tolerancesgond rh e, e p ihist he @KS??? due he iahric i he .h h' 'ss 9 ihshr ihe attainment o th se o erahces.

W ha e hhs than 9me o t e hie h hs p e i us y j... r d n the .ihhri at oh-of h eheproie ti lethp fi ahi hi have l ft m h o e$. e Qhw the e me'thods-cpmn ses ormin the Elaine??? immspace s lihs'? with the length of the wire in each filament snppgrt- 1%: 4999 b in a .i ihei qh'ef z the len th .Qi' heh h between. aeh "coi se men and" th hape. 9.? 9 90.! h ihen9 eier ihe -h the periphe a P0113135 a whiqh' the s a ed ert ion ta ts .hh eh 1 is'e dhther niethoii rit as been t e heti. to hehs e -t e' am mi ter it ha he h forme toe-firing "2.50 that when he ted o a temh athh s fifi i ht-to efl t a se ing the eof it. hav za precle-trrmihed orm When th lament is i me i rqm spa ed oi in om' oht hhqhs co n and trahs+ r ed t a i i iiat e ;c .ose-t lerahqe swahd i orm pa i g :des .he zabov ar uite .d.i.f: cu o att Wi h-.anv-.de r.ee o manufacture ing consistency;

hccordingly thereiore; an QbiiQQtfOf .,'o,ur- :inven; n i to ov de aa: methqd of iabr catingia @bih plane projecti n IamP -flament WhiQh is .char aeterized. by .uniiqrmity' in the {length .Qf the several-segmentsthereotfluniformity in the ;spac etbe eh th seementsmand unii rmitylinatne h ci e be een th -p1ai1es,:a11 very close telerames:

An her .Q ie 'risfitoaprqvide a method 'Qf fah qat h 1121 4116 pr je tion 3 .5 .1 1?- filament wh h; i rqharaq e iz r h uniform t inane: ac n zbeiw eh the .9QP ih l?Q q hr....e ehih h Q zeeehw hrhefer h hehmp he ih: 9th he hp izeht an the 'rehii' h -ah ah fahd uniformity in shape.

.Qhhihfiih dfiihhhsii the dea 19 =:?in ems uep ih iWBPinU- QS QHQ Q by P h-imeah -Partial euh ihdihsthe uous coiling to form the several segments of the (01. in -tum 2' projection lamp filament and the several loops thereb'e'vveer'i rrbm wnih the filament. is. slipp'cirtiil "This operation is' performed on a inan'd'rel which mayser've asthe firing' jig as well as'the' forming fixture; Q Y Further object's; advantages, and features will be apparent fro n'i the following description thereof when reaaim'eanjuncmun With t heae companying drawings inwhich: "Figure 1 isa perspective View of the. apparatus orpur'mvemios."

Figure 2 is a side elevatipnal view of a length of coiled-coiled. t ingsten Wire which is iolded and jiggecl on the apparatus of Figure 1. Figure 3 is a 'si'de'eleva-tionalview of the mandrel on which" the eoiled wire of Figure z'isfolded. f

Figure 4 is a side elevational view of the mandrel of Figure with-the 'coiled coiled wire folded t b a Figure 5 is a sideelevational view of the rear en'dbf the jigof Figure H igure -6 is a toplv ijew off the rear end. of the he o i her- Figiire' 7 is a top view, partly insection, of the i d of the-jig bf Figure 1'; Y

igure 8 is a 'sijc'le 'el'vational view of the front dh qhe g gfi -Figiire' i'sa'front view-pflthe front end of the jigof Figure 1."

Figure 10a, 0, 0, d, e, j and f! is a plurality of fra m ntary details illi is'trating" the trimmer in which the coiled coiled tungsten wireof Figure 2 isfoldedon the mandrel of Figure '3.

Ref(errir'ig to theapparatus of our.

i Slid l8= :By h eh t is w, an qp ic i b e-t0 lqqketh e fiend an he a nded -19 1 0 @QllfifiIlQ'fihfi a d th cas n 5: Th Qute leh o the sl d 8 n 9 arezpwd d -:W -late th1 extendin r ie en her na t referre to a u de he v 312 we 13 respectively; {IZhemovable slide 9 is provided witha sc e 1-4 extehdi i te a ther om; o

serve as a handle by which an operator may move the slide outwardly, the purpose of which is described more fully below, and as a stop for limiting the inward movement thereof.

The manner in which the jig I is mounted in block 2, and the block 2 is mounted on support 3 is illustrated in Figures 1, 5 and 6.

The jig I is rotatably mounted in block 2 by means of a shaft I5 which projects from an end of the jig and through an aperture therefor in the block, and a ring I6 locked to the shaft I 5 by set-screw II. The adjacent engaging faces of the ring I8 and the block 2, are provided with means for indicating to an operator when the jig has been rotated 180 degrees, the purpose of which will be described more fully below. This means comprises a pair of dimples I8 in the ring I6 and a spring biased ball I9 in the block 2. A

spring 28, seated in an aperture therefor in theblock 2, is placed under tension by a set-screw 2|, thereby exerting a force which tends to effect v a seating of the ball I9 in a dimple I8.

The block 2 is secured to the support 3 by means of a locking screw 22 which extends through the support 3 into a threaded aperture therefor in the block 2. This arrangement permits the angle of elevation of the jig I to be adjusted so that it may be located in the most satisfactory working position for any given operator.

Figures '7, 8, and 9 show in detail the slides 8 and 9 and the mandrel IIl therebetween, and the manner in which these members are seated in the chamber 5 provided therefor in the casing 5. The mandrel I6 is a'plate of high refractory material such as molybdenum for example, and is provided with a plurality. of lateral slots 23 on both faces adjacent one end thereof, and a plurality of indexing grooves 24 on a face ad jacent the other end thereof (Fig. 3).

As shown in Figure 7, the slides 8 and 9, which are elongated metal members, are provided on their adjacent, engaging faces with cooperating longitudinal grooves which define a chamber for the mandrel I8. These grooves are deeper at the exposed ends of the slides to provide space for the several segments of the filamentary coil when it is folded on the mandrel I9 (Figures 7 and 9). The fixed slide 8 is pivotally mounted on a pin 25 which prevents longitudinal movement thereof in the chamber 8. As shown in Figure 7, the fixed slide 8 is provided with a resilient spring member 26, one end of which is fixed to the slide and the other end of which is engageable with the indexing grooves 24 on the mandrel I9, the purpose of which is described below.. The outside ends of the slides B and 9 adjacent the guide shelves I2 and I 3 respectively are cut away as at 27 to provide space for the filamentary coil during each folding cycle and to insure proper insertion of a forming tool between the turns of the coil.

The method of forming, from continuous coiling, segmented coils having uniform loops between adjacent segments, on the above-described apparatus, is illustrated in the several views which comprise Figure 10, when read in conjunction with the other figures, particularly Figures 1, 7, 8 and 9." The jig 1 is oriented by positioning it so that the locking screw II is on the left side thereof from an operators point of view. The screw I I is loosened, and the mandrel I9 is inserted in the chamber therefor defined by the longitudinal grooves in the engaging faces of the slides 8 and 9; with the indexing grooves on the side adjacent the fixed slide. The mandrel is properly seated when it comes to rest with the first indexing groove against the resilient spring member 26 attached to the fixed slide 8.

seated, the mandrel I0 is thrust in until the spring 26 seats in the next indexing groove in the mandrel. At this time the end segment 29 of the coil willbe positioned in the groove 23 in the mandrel and against a face of slide 8. The screw II is tightened to lock the mandrel III within the slides 8 and 9 and the slides to the casing 5. Folding of the wire 28 about the mandrel III by bending and partially unwinding it is accomplished by an operator with the aid of a pair of forming tools 30 and 3I, each of which is preferably provided with a beveled tip 32 and 33 respectively.

Forming tool 30, with the bevelled side 32 up, is positioned fiat on the surface of the guide shelf I2 and is moved in the direction of the slot in the opposite side of the mandrel and into engagement with the coil 28 (Figure 10a) until it is more than half way. past the longitudinal center thereof between the two adjacent turns of the coil at the plane of the upper edge of the mandrel. With forming tool 33 thus seated, forming tool 3! is moved into position flat on the surface of the bevelled edge 32 of the tool 30 and in engagement with the coil 28 (Fig. 10b). Tool 3 I is then raised and rolled forward slightly until the coil 28 is disposed substantially perpendicular to the segment 29 thereof (Fig. and is extending in the direction of the slot in the opposite face of the mandrel (Fig. 100). Both tools are then withdrawn from engagement with the coil 28.

With the first forming tool 30 held vertically, and the bevelled side 32 to the right, the operator brings it into engagement with the coil 28 so that one turn thereof, turn 35, is disposed on the left side of the tool (Fig. 1001). Turn 35, after the folding operation has been completed, defines a loop by means of which the filament may be supported in a lamp. With the first forming tool 39 thus positioned, the second forming tool 3| is brought into engagement with the bevelled edge 32 of tool 38 (Figure '10e). A rotary forward movement is imparted to the tool 3|, thereby effecting a further bending and partial unwinding of the coil 28 and causing it to move downwardly into a slot 23 on the right side of the mandrel I0 (Figure 10]). The operations just described also result in a twisting of the wire at I the points of application of the tools to the wire.

Tools 38 and 3| are then removed from engagement with the coil 28; Segment 36 has now been formed and is disposed as shown in Fig.

10f. The locking screw I I (Figures 1 and 7) is now loosened, and the movable slide 9 is drawn forwardly a distance sufiicient to enclose segment 36 of the coil 28 which has'just been positioned in a groove 23 on the right side of the mandrel I0 (Fig. 10 and 7), with the lip of the slide 9 covering and holding segment 38 in poscrew II is then tightened. V

The jig I is then rotated clockwise degrees to properly position the several parts thereof for the next operation. When this is done, the unfolded portion of the coil 28 is then disposed in the same relative position as that in which the coil 28 is shown in Figure 100., except that the movable slide 9 instead of the fixed slide 9 will now be disposed on the left. The sequence of steps described above and illustrated in the several parts of Figure 10 is then repeated. Upon completion thereof, the screw l I is loosened, and the mandrel l9 and slide 9 are pushed inwardly together one indexing position on the indexing grooves 24 (Fig. '7).

The operation of folding the coil 28 by bending and partially unwinding it on the mandrel I9 to form a plurality of segments is continued with the folding steps performed as described above and illustrated in the several parts of Figure 10 and the jig rotated 180 degrees after each segment has been positioned in its proper slot 23. The relative position of the mandrel l9 and the movable slide 9 is adjusted after each folding cycle by alternately drawing the slide 9 forward and pushing the mandrel l9 and slide 9 inward, as described above. The slide 9 is drawn forward when it is on the operators right, and the mandrel I0 and slide 9 are pushed in when the slide 9 is on the operators left.

After the folding of the coil 28 on the mandrel I0 has been completed, the mandrel I9, with the coil 28 folded thereon, is withdrawn from the jig l and may be positioned on a suitable fixture and fired to effect a setting of the coil.

Although the method of our invention has been specifically described and illustrated with reference to the fabrication of bi-plane electric lamp filaments, its adaptability to the fabrication of other segmented electric lamp filaments will be readily appreciated by those skilled in the art. For example, segmented mono-plane filaments may be readily fabricated by folding all or the filament segments on one side of the mandrel.

0 Number 6 What we claim is: I In the method of forming an electric lamp fila ment from a continuously uniform wound coil of filament wire, said filament having a plural ity of coil segments with a filament supporting full circular loop between each pair of segments, said method comprising fixedly holding the continuously uniform wound coil of filament wire adjacent one end thereof, bending the free portion of the continuously wound coil of filament wire until it lies substantially perpendicular to the fixedly held portion thereof, said held portion defining the first coil segment of the electric lamp filament, holding the next complete loop of the free portion of the coil against shifting, and, while so holding the complete loop, further bending the remaining free portion of the coil until it is parallel to the first coiled segment, and sequentially executing the above defined steps on the remaining free portion of the continuously wound coil until the filament forming operation has been completed.

OLIVER MANN.

RALPH B. THOMAS.

References Cited in the file of this patent UNITED STATES PATENTS Name Date Schroter Jan. 9, 1912 Jarman July 6, 1926 Fehse Aug. 27, 1929 Dedrick May 2, 1933 Stenwall Aug. 30, 1938 Iden Apr. 20, 1948 Isaac Sept. 21, 1948 Hayes Nov. 23, 1948 FOREIGN PATENTS Country Date Great Britain Jan. 6, 1948 Number 

